The Off-Key Bard
History

This Day in History — The Night the Northeast Went Dark

On this day in 1965

On November 9, 1965, one backup relay near Niagara Falls opened a line, and within minutes about 30 million people in the Northeast and Ontario lost power.

The Off-Key Bard stands on a Manhattan sidewalk on the evening of November 9, 1965. Office workers are leaving the skyscrapers, subway platforms are filling with commuters, and cars crowd the intersections beneath a skyline just beginning to glow against the dusk. Then the lights flicker. Some dim. Others brighten for a moment. Hundreds of miles away, near Niagara Falls, a protective device has just disconnected a transmission line, and the consequences are already racing across one of the most heavily populated regions of North America.

"The lights aren't going out because the power stations have stopped producing electricity. They're going out because an interconnected system is losing its ability to deliver it."

On November 9, 1965, the Great Northeast Blackout left about 30 million people without power across the northeastern United States and Ontario, over roughly 80,000 square miles. In New York City the lights went out at about 5:27 p.m., at the height of the evening rush hour. It was not a storm, an earthquake or an attack. It began with a protective relay doing exactly what it had been set to do, and the lesson it taught engineers is still being taught.

How the Grid Grew Together

In the early decades of electric power, a generating station might serve one neighborhood or one factory district. As demand grew, stations got larger, transmission lines carried power farther, and utilities tied their systems together. The advantages were real: a region with a surge in demand could draw on another's spare capacity, and hydroelectric power from places like Niagara could serve distant cities.

The price of that connection is that trouble in one place can be felt far away. A large alternating-current network is not a pipe with water in it. Generators, transformers, lines and loads have to operate together, and generation has to stay matched to consumption. Lines that carry too much current overheat, so engineers install protective relays, which watch conditions and tell a circuit breaker to open when something looks dangerous. A relay that is set too sensitively can disconnect equipment that should have stayed in service, and the loss of that equipment shifts the strain onto the rest of the network.

The Relay at Beck

The weak point was a backup protective relay associated with the Sir Adam Beck No. 2 hydroelectric station near Queenston, Ontario. The Federal Power Commission's investigation found that the backup relays protecting five 230-kilovolt transmission lines had been installed in 1951 and that their settings had been modified in January 1963. One relay was configured to operate under conditions corresponding to approximately 375 megawatts of power flow and 100 megavars of reactive power at a specified voltage. Its purpose was to provide backup protection if other relays or circuit breakers failed, not simply to disconnect a line when it reached its maximum carrying capacity.

By November 1965, the operating conditions had changed. Trouble at another Ontario generating station had increased the amount of power moving through the Beck interconnections, reducing the margin between normal operation and the backup relay's operating threshold. At 5:16 p.m. on November 9, the relay operated under the conditions it detected and disconnected a transmission line that had not suffered an electrical fault. The relay was following its configuration, but that configuration was no longer adequately coordinated with the system's operating conditions. The result was the first step in a cascading failure that spread far beyond the original line.

Five Lines in Three Seconds

At approximately 5:16:11 p.m., the backup relay disconnected one of five 230-kilovolt transmission lines associated with the Beck station. The power previously carried by that line was redistributed across the four remaining lines, pushing their operating conditions beyond the thresholds of their own backup protective relays. According to the contemporary engineering account of the Federal Power Commission investigation, the remaining four lines disconnected within 161 electrical cycles, approximately 2.7 seconds. A protective action intended to isolate trouble on one part of the network had instead removed an entire group of important transmission paths. The disturbance then spread through the interconnected system as power flows shifted, additional protective devices operated, and generating stations became separated from the loads they served.

From there it was a cascade. The generators at Niagara were still producing power, but the paths that carried it away had disappeared. The surge pushed into the New York network, more protective devices operated, and the interconnected system broke apart into pieces that could not hold together. Generators shut themselves down, and frequency dropped. A WABC aircheck from the evening, as described in Wikipedia, shows the line frequency at about 56 hertz roughly six minutes before the blackout and about 51 hertz two minutes before it. Hackaday says the outage reached its fullest extent at about 5:28 p.m. By Chiles's estimate, the United States briefly lost one-fifth of its electricity.

Counts of what was affected vary. Wikipedia says over 30 million people, and notes that a quoted New York Times passage from 1965 said "perhaps 25 million." Hackaday says six states and one Canadian province, while History.com counts eight states and the provinces of Ontario and Quebec.

New York Goes Dark

At about 5:27 p.m. the lights sputtered and then went out across Manhattan, the Bronx, Queens and most of Brooklyn. A Flatiron NoMad Partnership history gives 5:28 p.m. and notes that the temperature was in the mid-40s with a clear sky.

The subway stopped. The Flatiron history says 630 trains halted in tunnels, on elevated tracks and in stations, and cites the New York Times for about 800,000 stranded riders. EBSCO and Hackaday say about 600,000, so the figure is best read as hundreds of thousands. Police and firefighters led riders out along catwalks and tunnels. EBSCO says that by midnight about 90 percent had reached the nearest exits, while the Flatiron history says about 10,000 were still stuck at midnight. At the Empire State Building, thirteen elevators stalled with people inside, and EBSCO reports that six were emptied using ladders lowered from above while reaching the rest required breaking into the shaft walls. Hospitals delivered babies and finished operations by candlelight, according to EBSCO, and air-traffic controllers lost contact with incoming planes.

Wikipedia says a bright full moon lit a cloudless sky. Some commuters slept in stalled train cars or on the floor of Grand Central Terminal. The Flatiron history, citing Time, says some New Yorkers believed a passing satellite meant the Russians were responsible, while others thought it was a government air-raid test. Both were rumors, not findings.

Calm in the Dark

What did not happen was the breakdown some feared. EBSCO says most New Yorkers responded with helpful cooperation, with volunteers directing traffic at street corners. ABC7 describes people stepping in to help where they could. The Flatiron history reports that passengers struck up conversations and that most of the irritation came out as sarcasm. Wikipedia says only five looting reports were made in New York City that night, which it calls the lowest crime on any night in the city's recorded history. It also says reports of a baby boom nine months later are unsubstantiated.

Radio stations had their own struggles. In a December 1965 article in Broadcast Engineering, George C. Sitts describes WCBS switching to diesel generators, WABC going off the air for about 15 minutes while its emergency generator started, and WINS engineers filing reports with battery-operated tape recorders over telephone lines so reporters did not have to climb 19 floors to the studio. WQXR had no emergency power and went silent for the first time in 25 years.

Getting the Lights Back

Restoring a collapsed grid is not a matter of throwing one switch. Generators have to be brought up under controlled conditions, lines reconnected, and separate sections synchronized before they can safely run together. Hackaday reports that upstate, hydro plants supplied excitation current, while downstate diesel generators were used, and that neither nuclear plant in the area was online. Chiles notes that steam generators could need about eight hours to restart once they had shut down.

Some less populated areas were back within a minute. ABC7, citing the Associated Press, says power returned to Canada by 8 p.m., upstate New York by 9 p.m. and Massachusetts by 10 p.m., with New York City the last to recover and power returning around 3:30 a.m. on November 10. Other accounts run longer. Wikipedia says parts of Brooklyn were repowered by 11 p.m. and the rest of that borough by midnight, and that the entire city was not back to normal until nearly 7:00 a.m., and several sources give up to 13 hours for the longest outages. The accounts are best reconciled as power returning in stages over the night, with 13 hours as the longest outage.

The Investigation

Within hours, according to Hackaday, President Lyndon Johnson ordered the chairman of the Federal Power Commission to study the cause. A report came out on December 6, 1965, which Hackaday describes as "tentative," with recommendations that included more frequent checks on relay settings and creating a body to oversee national electrical reliability. The commission's full report, Prevention of Power Failures, was published by the Government Printing Office in 1967. EBSCO says it made 34 recommendations.

The findings were not that the region lacked power. Chiles notes that the Northeast had enough generating capacity but too few interconnecting lines, and that control centers and generating stations had depended on system power and were left without backup. The recommendations EBSCO summarizes were practical: emergency generators for hospitals and airports, emergency lighting in stairwells and elevators, battery backup for communications equipment, auxiliary power at coal-fired plants, better balance between generation and transmission, computers for rapid analysis and control, and better emergency training for control-room operators.

What Changed

Utilities changed their practices. Chiles says Ontario Hydro raised relay settings, utilities added relays to break interconnections during surges, and automatic load shedding became an industry standard within two years. On June 1, 1968, the industry formed the National Electric Reliability Council in response to the blackout, according to NERC's milestones list. The council became the North American Electric Reliability Corporation on January 1, 2007.

The blackout was one factor, among others, in the creation of the Electric Power Research Institute in 1972, according to Wikipedia, which names Chauncey Starr as its founder and first president.

Another cascading outage struck on August 14, 2003, when NERC says about 50 million people lost power in the northeastern and midwestern United States and Ontario. The Energy Policy Act of 2005, signed on August 8, 2005, authorized a self-regulatory electric reliability organization with FERC oversight and made compliance with reliability standards mandatory and enforceable. FERC certified NERC in that role on July 20, 2006.

A relay tripped, the current strayed,
And city lights began to fade.
From tower bright to darkened street,
The grid revealed its fragile beat.

The Great Northeast Blackout is not only a story about one relay with the wrong setting. A device designed to protect equipment opened a line it should not have opened under the conditions of that evening, the load moved to other lines, more protective devices operated, and the network could no longer hold together. A component can do exactly what it was configured to do and still help cause a disaster if the configuration does not fit the larger system.

The event also showed something about the people who depended on the grid. When the lights went out, they improvised. They directed traffic, helped strangers out of tunnels and elevators, and waited out the night. Electricity had become so woven into daily life that losing it for an evening could halt a region, and that dependence has only grown. The more tightly technology is connected, the more important it is to understand how a local failure can spread through a system that looks stable under ordinary conditions.

Sources

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